Idukki Dam releases water when Kerala is in Floods: Could this have been avoided?

Kerala is facing serious floods. Army, Navy, NDRF, neighbouring states are all out. Dozens of people have died, landslides happening, houses washed away, the whole machinery is out to deal with the crisis.

In this flood crisis, Idukki & Idamalayar two of the Kerala’s biggest dams along with about two dozen others, are releasing water, adding to the floods and the disaster. Why are Idukki and Idamalayar, both having live storage capacity above a Billion Cubic Meters, releasing water NOW, when whole of Kerala is facing floods due to recent excessive rains? Standard excuse: The dams are full and they have no option but to release the water, they cannot store more. But why did they wait to start releasing water till the dams are full and they are faced with TINA: There is No Alternative. This love to be in TINA situation seems like a disease affecting all dam operators.

 

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Slideshow of screenshots showing how flood water would travel from Idukii dam to Arabian sea affecting human habitation along the course.  (Image Source: Manorama 31 July 2018) 

There are still two months of South West Monsoon for Kerala. Then large parts of Kerala also get benefits from North East monsoon that follows in Oct-Dec. In fact, the only two occasions (1981 and 1992) when the gates (shutters) of Idukki dam were opened since the Idukki Dam was commissioned in 1975, were both during North East monsoon, never in SW monsoon. The filling up of the reservoir by end of July was an unprecedented situation and KSEB, Kerala Govt and CWC should have demanded that the dam gates should be opened to release the water as soon as possible.  

So they could have easily taken advance action to release water from Idukki when Kerala was not facing floods. They obviously did not and now, when Kerala is facing floods, Idukki is adding to Kerala’s misery.

In fact, just about ten days back, on July 31, 2018[i], the media was full of stories of possible release of water with water level in Idukki crossing 2395 ft, with FRL at 2403 ft. If they had started water in the intervening relatively dry period, Idukki dam need not have added to Kerala’s flood disaster misery. They did not. WHY? Why they again waited to be in TINA state when Kerala is also facing floods?

In fact, basic objective of Idukki Dam is power generation. Idukki dam has six turbines with 130 MW capacity each. One expected that this year Idukki power generation would have broken all records, since never before has the dam water level and inflows into the dam been so high. But when one looks at daily and monthly power generation figures from National Power Portal of Central Electricity Authority (CEA) and CEA’s own past records, one is shocked to see that during June-July 2018, Idukki generated about 325 Million Units (MU) of power, which was below power generated during at least four years in just last decade: below that in 2008, 2012, 2014 and 2015. In 2014, the highest generation year for June-July, Idukki generated over 50% more than it generated in June July 2018. If Idukki had generated more power, that could have also help reduce water level.

So why did Idukki power not generate more power when so much water was available. National Power Portal[ii] provides the answer: one of the six 130 MW units of Idukki has been under shut down since Aug 1, 2017 for Renovation/ modernisation and another 130 MW unit is under shut down since June 26, 2018 for annual maintenance. Its of course a mystery why the second unit was taken out for annual maintenance during monsoon, when it could have been done in dry season. But the consequences of this actions are that Idukki produced less power and it also added to flood disaster misery of Kerala.

In fact, even before the SW monsoon set in this year, on May 31, 2018, Idukki’s live storage capacity was 25% full, much higher than normal and higher than previous year or average of last ten years. That also contributed to the dam filling up sooner. Why such high water storage before the onset of monsoon is a question that the Idukki managers will need to answer.

Kerala Rainfall As per IMD (India Meteorology Department) figures, till Aug 9, Kerala received 20% above normal rainfall. Idukki districts tops with 50% above normal rainfall and also highest rainfall among all districts of Kerala so far: 2433.5 mm. Palakkad (44%), Kottyam (36%) and Ernakulam (33%) are some other districts having high surplus rainfall. But it’s possibly the bouts of high intensity rainfall that has created the current situation.

CWC has no flood forecasting sites at all in Kerala The unprecedented floods and dam water releases also raise the questions about flood forecasting and advance action by Central Water Commission (CWC), India’s only flood forecasting agency. When we see CWC’s FF website, we are shocked to find that CWC has absolutely NO flood forecasting sites, neither level forecasting, nor inflow forecasting. CWC has only flood monitoring sites in Kerala, and as the table below shows, at least one of them is non functional. Its high time that CWC includes some key dams like Idukki and Idamalayar and some key locations in its flood forecasting.

List of CWC Level Monitoring Sites, in Kerala

SN	Site	River	Basin	District	HFL, M	Date
1	KALAMPUR	Kaliyar	WFR south of Tapi	Ernakulam	14.96	NA
2	RAMAMANGALAM	Muvattupuzha	WFR south of Tapi	Ernakulam	8.42	NA
3	VANDIPERIYAR	Periyar	WFR south of Tapi	Idukki	793.8	NA
4	NEELEESWARAM	Periyar	WFR south of Tapi	Ernakulam	11.105	27-07-1974
5	PERUMANNU	Valapatnam	WFR south of Tapi	Kannur	14.75	07-08-2012
6	ADKASTHALA	Shiriya	WFR south of Tapi	Kasaragod	NA	NA
7	ERINJIPUZHA	Payaswani	WFR south of Tapi	Kasaragod	19.08	12-07-1995
8	KIDANGOOR	Meenachil	WFR south of Tapi	Kottayam	8.015	NA
9	KUTTYADI	Kuttyadi	WFR south of Tapi	Kozhikode	8.32	18-07-2009
10	KARATHODU	Kalalundi	WFR south of Tapi	Malappuram	13.5	18-07-2007
11	KUNIYIL	Chaliyar	WFR south of Tapi	Malappuram	10.63	14-07-1984
12	MANKARA	Bharathapuzha	WFR south of Tapi	Palakkad	51.55	NA
13	KUMBIDI	Bharathapuzha	WFR south of Tapi	Palakkad	9.76	18-07-2007
14	PUDUR	Kannadipuzha	WFR south of Tapi	Palakkad	65.55	NA
15	PULAMANTHOLE	Pulanthodu	WFR south of Tapi	Palakkad	19.07	14-07-1994
16	THUMPAMON	Pamba	WFR south of Tapi	Pathanamthitta	13.735	NA
17	KALLOOPPARA	Pamba	WFR south of Tapi	Pathanamthitta	9.31	NA
18	MALAKKARA	Pamba	WFR south of Tapi	Pathanamthitta	8.2	NA
19	PATTAZHY	Kalladda	WFR south of Tapi	Quilon	13.805	NA
20	AYILAM	Vamanapuram	WFR south of Tapi	Thiruvananthapuram	10.685	NA
21	ARANGALI	Chalakudy	WFR south of Tapi	Trichur	7.61	NA
22	MUTHANKERA	Kabini	Cauvery	Wyand	712.735	22-06-1992

 

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CWC’s hydrographs showing Rivers Kabini, Bharatpuzha & Valapatnam unprecedentedly crossing highest flood levels. 

In Conclusion Its clear that major storage dams of Kerala like Idukki and Idamalayar, by releasing water when Kerala is facing floods due to widespread heavy rainfall, are adding to the flood misery of Kerala. This could have been avoided if the dam operators had started releasing water in advance rather than waiting for dams to be filled up, when they have no alternative but to release water. Its also clear that there was sufficient time and relatively dry period when they could have released water, rather than when Kerala is facing floods. If the Idukki power unit that was taken out or operation from June 26, giving “Annual Maintenance” as reason was in stead taken for annual maintenance during drier summer months, that would have helped, particularly when one unit is already out for renovation. If the water level in Idukki was lower before the onset of monsoon, it would have helped. CWC’s absence in flood forecasting is also additional handicap.

All this requires action. Possibly one of the first things, post current phase of rescue and emergency, that Kerala govt can do is to institute an independent inquiry into these issues, so that such situations do not recur, when dams, in stead of helping moderate the floods, add to the flood misery.

Himanshu Thakkar, SANDRP (ht.sandrp@gmail.com)

END NOTES:

[i] https://www.thehindu.com/news/national/kerala/water-inflow-slows-down-in-idukki-dam/article24565074.ece, https://www.business-standard.com/article/pti-stories/idukki-dam-alert-continues-as-water-level-nearing-maximum-118073101490_1.html, https://english.manoramaonline.com/news/kerala/2018/07/31/idukki-dam-shutters-opened-reasons.html

[ii] https://npp.gov.in/public-reports/cea/daily/dgr/31-07-2018/dgr7-2018-07-31.pdf